I experienced a lot of issues due to soil or due to me but reinforced by the soil proprieties ( over and under watering ). And as I am recuperating my old soil for my new growth I can have issue due to the old soil , sometimes a fungus did settle in the soil and is killing my 2nd grow. You also said living soil and I bet that too much mineral feeding can kill the Micro life in the soil. And to finish as you are riding the grow questions with me this month you can see that a lot of peoples are experiencing issues in soil , not only under and over feeding